The modern communications era has brought about a tremendous expansion of communication networks. Communication service providers and device manufacturers are continually challenged to deliver value and convenience to consumers by, for example, providing compelling network services, applications, and contents. The development of communication technologies has contributed to an insatiable desire for new functionality. Portable communication apparatuses (for example, mobile phones) are no longer just tasked with making telephone calls. Users could chat with strangers nearby using mobile devices first and then decide to meet with each other for a direct face-to-face contact, for example, for the purpose of purchasing ‘buy 3 pay 2’ or series goods together. This kind of thorough pervasive social communications is an essential and valuable compensation for not only Internet social networking, but also traditional social communications. In such a situation, it is important to make a recognization mechanism for strangers to meet with each other in a secure and easy way.